Abstract:
The effects of bright light on circadian rhythms in man are well documented. Nevertheless the theoretical basis and the rules for the practical utilization of light exposure as therapy need still to be better defined. The present study determined to what extent a 2-hr bright light exposure (0500-0700 h) improved the adjustment to an early rising in normal adults. Phase changes were assessed in subjective alertness, performance in several search tasks, time estimation, and a visual discrimination task, as well as in body motility, plasma cortisol concentrations, and body temperature. In comparison with a dim light exposure, the bright light resulted in increased motor activity during waking, in earlier peak of subjective alertness, and an improvement in performance speed in three out of five tasks in the morning. Cortisol and body temperature also were phase-advanced. In summary, light applied to a portion of the circadian cycle sensitive to phase advance shifts influenced rhythms with strong endogenous components (temperature and cortisol), while other rhythms with strong exogenous components were more sensitive to sleep deprivation caused by the early rising time.
摘要:
强光对人的昼夜节律的影响是有据可查的。然而,仍然需要更好地定义光暴露作为治疗的实际利用的理论基础和规则。本研究确定了2小时亮光暴露(0500-0700小时)在多大程度上改善了正常成年人对早期上升的调整。以主观警觉性评估相位变化,在多个搜索任务中的性能,时间估计,和视觉辨别任务,以及身体运动性,血浆皮质醇浓度,和体温。与昏暗的光线相比,明亮的光线导致清醒时运动活动增加,在主观警觉性的早期高峰,以及早上五个任务中有三个的执行速度提高。皮质醇和体温也是相提前的。总之,施加到对相位提前偏移敏感的昼夜节律周期的一部分的光影响具有强内源性成分(温度和皮质醇)的节律,而其他具有强外源性成分的节律对起步时间早引起的睡眠剥夺更敏感。